1. Field of the Invention
The present invention relates to a communication system. More particularly, the present invention relates to a system and method for using frequency and time resources in a communication system.
2. Description of the Related Art
In a communication system, a transmitter can transmit a signal in at least one of Frequency Division Duplexing (FDD), Time Division Duplexing (TDD), and a combination of FDD and TDD (Hybrid Division Duplexing (HDD)).
FIG. 1A illustrates a conventional use of resources in an FDD communication system.
Referring to FIG. 1A, the FDD communication system divides a total frequency band into two frequency subbands, for example, a first frequency subband 101 and a second frequency subband 103. There is a guard interval 105 located between the first and second frequency subbands 101 and 103 in order to prevent interference.
The first frequency subband 101 is used for UpLink (UL) transmission and reception, and the second frequency subband 103 is used for DownLink (DL) transmission and reception.
FIG. 1B illustrates a conventional use of resources in an HDD communication system.
Referring to FIG. 1B, the HDD communication system divides a total frequency band into three frequency subbands, for example, a first frequency subband 111, a second frequency subband 113 and 115, and a third frequency band 117. The first frequency subband 111 is used for UL transmission and reception. The second frequency subband 113 and 115 are divided into a TDD DL band 113 and a TDD UL band 115, for DL and UL transmission and reception, respectively. The third frequency subband 117 is used for DL transmission and reception.
Guard intervals 119, 121 and 123 are located between the first frequency subband 111 and the second frequency subband 113 and 115, between the second frequency subband 113 and 115 and the third frequency subband 117, and between the TDD DL band 113 and the TDD UL band 115 in order to prevent interference. The guard interval 123 is called a Transmit/Receive Transition Gap (TTG) or a Receive/transmit Transition Gap (RTG).
As described above, a guard interval is interposed between frequency subbands to avoid interference in the communication system. Since the guard interval is an empty frequency band, a waste of resources may result.